Devices for distributing air are generally known in air conditioned rail vehicles with air conditioning systems which are mounted in the roof area. In these devices, the treated air is fed from the air conditioning system, frequently arranged on the roof of the vehicle, to main venting ducts using air feed ducts, said main venting ducts being located between the roof and the inner ceiling of the vehicle. These air feed ducts lead from the air outlets of the air conditioning device to openings which are located in the main air ducts. Because of the external and internal dimensions of the vehicle which are always limited, the space between the underside of the air conditioning device on which the air outlets are located and the upper sides of the main venting ducts is very small. This small space results in the cross sections of the air feed ducts being limited and as a result there are generally high flow speeds of the air, which in turn generate a high level of noise. This relates to vehicles in which the heating power from the air conditioning device which is conceived as a roof-mounting device is introduced into the passenger compartment via at least one separated-off duct which runs longitudinally in the roof area. The heating air duct is therefore separated off from the cold air duct. Different volume flows for the heating air and cooling air are necessary for different climatic zones. This is problematic for a vehicle which is to be operated in regions with different climates since even higher air speeds would occur in certain climatic zones.
The document DE 101 49 594 A1 is concerned with the previously described problems and provides the largest possible embodiment of the cross sections for the air conditioning ducts, in which case the air conditioning ducts are additionally assigned static functions and as a result installation space for load bearing elements is saved. However, when the cross section is divided into two fixed areas the utilization of the cross section is defined and therefore does not permit the optimum flow speeds when a component duct is not used.